Specimens of 53 females and 11 males of an unknown spider species from the family Theridiidae in Japan were taxonomically studied. The spider is identified as Chrysso subrapulum Zhu, 1998 known only from males from China, which is recorded here from Japan for the first time. This species is described based on the Japanese specimens, including hitherto unknown females, and is transferred from the original genus Chrysso O. Pickard Cambridge, 1882 to the genus Chikunia Yoshida, 2009 via a comparative examination of morphological characteristics. A nomenclatural problem with the specific name of this spider is discussed and its original spelling must be used for it.

Faunal survey of dragonflies and damselflies in the Akasaka Imperial Garden, Tokyo, was conducted during 2012 to 2022, and recorded a total amount of 38 species including some species possibly occasionally came from outside (e.g. Anotogaster sieboldii). Previous study from 2002 to 2004 by Saitô et al., (2005) reported 24 Odonata species from the garden. In comparative with this record, additional 16 species are newly recorded by our survey but two species were not re-observed. Almost all the recorded species are lentic ones. It would be caused by the scarcity of lotic environment in the garden. A total of 12 threatened species ranked in the red list concerned with the biota of Tokyo (Natural Environment Division, Bureau of Environment, Tokyo Metropolitan Government, 2023) is found. This result could be one of rationales for the continued preservation of the Akasaka Imperial Garden, one of precious urban greens in the Tokyo metropolitan area.

Based on the material obtained in Kôshû City, Yamanashi Prefecture, Honshu, observations on the oviposition and results of the rearing experiments of Pamphilius benesi Shinohara, 1985, are presented, the life history of this sawfly is outlined, and the immature stages and the larval leaf-rolls are briefly described and illustrated.

The known crab species of the Ogasawara (= Bonin) Islands, Tokyo, Japan, are updated, with the literature and localities concerned. In Table 1 are the definitely identified 314 species from the three island groups, Muko-jima (= Keetaa I.), Chichi-jima (= Peel I.) and Haha-jima (= Coffin I.) Groups, and also, 35 species from the southernmost Iwo-jima (= Sulhur I.) Group, and two solitary islands, Nishino-shima (= Rosario) Island and Okino-Torishima (= Parece Veta) Island are listed in Table 2. Otherwise, in Table 3, the deep-sea 10 species reported from the seamounts off the Ogasawara Islands are listed. Eight of 35 species (in Table 2) and 4 of 10 species (in Table 3) are unrecorded from three main island groups, and thus a total of 326 species are known from the sea around the Ogasawara Islands.

A single specimen of the samarid flatfish, Samaris spinea Mihara and Amaoka, 2004, was collected off the northwest coast of Ototo-jima Island, Ogasawara Islands, Japan. This specimen represents the third occurrence of this species and the second record from Japan and the Northern Hemisphere. We report morphological characters of the specimen in detail with discussion of small spines along the dorsal and ventral margins of the caudal peduncle and the intermuscular bones. We confirmed the small spines coming out from large, plate-like scale. It is also revealed that distributional patterns of intermuscular bones of S. spinea are different from those of the congeneric species, S. cristatus: epimerals are absent and hypomerals are present only on abdominal and anterior caudal vertebrae in S. spinea. Although the present specimen bears a testis, male character as prolonged anterior dorsal- and pelvic-fin rays on ocular side is not appeared. This may be related to the presence of a single isopod parasite in the gill. The taxonomic confusion on gender of the generic name is also fixed.

A new boxfish, Kentrocapros flavimaculatus, is described on the basis of two specimens collected from New Zealand. The new species is distinguished from all other species of Kentrocapros by the following combination of characters: many yellow spots on the lateral sides of the body, a distinct spine on the middle of each dorsolateral ridge of the carapace, no spines on the lateral and ventrolateral ridges, and the gill opening located below the posterior half of the eye.

The ulnar antebrachial branch of the median nerve (UABM) was found in the right forelimb of a female western gorilla (Gorilla Gorilla) estimated 40 years old. It branched off the median nerve at the anterior aspect of the elbow and ran ulno-distally in the forearm toward the wrist. In the distal forearm, it bifurcates into the ulnar and radial bundles; the ulnar bundle is a sensory branch and the radial one is a motor branch. The radial one goes around the hook of the hamate deep into the palm and then radially as the deep branch of the ulnar nerve does in the human hand. The radial bundle innervates ulnar intrinsic muscles (all intrinsic muscles except for thenar muscles and radial two lumbricals). The proximal-ward intraneural dissection revealed that most nerve fibers of this UABM come from the medial cord and some from the lateral cord, and that further proximally one half of fasciculi coming from the medial cord originates from the medial division (Eisler) of the middle trunk·C7 root and the other half from the lower trunk·C8 root. We are not sure that this branch of the median nerve innervating the ulnar intrinsic muscles of the hand is the common structure of the nervous system in the forelimb of the gorilla.