The rhino mouse first described dy Howard in 1940, is a mutant which is characterized by wrinkled skin without hair resembling that of a rhinoceros. The autosomal recessive gene hr^rhwas reported to be an allele of the hairless gene and to be grouped into the 3 rd linkage. This mouse has been used extensively as experimental tool for researches on the inheritance of phenotypic expression, morphological characteristics, effects of X-irradiation or ultraviolet light, carcinogenesis, and skin metabolism. Recently, in our laboratory the homozygous rhino mouse was shown to have lesions resembling those of connective tissue disease associated with morphological and functional abnormalities of antibody forming tissues. It also showed a striking response to vitamin A and some carcinogens. The present review will outline some of characteristics of the rhino mouse with special reference to immunological ones, in comparing with those of the nude mouse also having cutaneous and lympho-reticular abnormalities.

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A new plumage color in Japanese quail, designated as“panda”, was investigated. In this variation, most of contour feathers are white except some limited areas in the head, back and tail where wild-type feathers appear as spots.“Panda”plumage seems to be controlled mainly by an autosomal recessive gene tentatively designated as“s”, and it resembles genetically and phenotypically with so called“brown splashed white”reported by K. Shimakura [9] . The major difference between the two is white wing feathers like panda never appears in the latter

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Fatal infection was established in mice inoculated perorally after fastig for 24 hours with 5×10⁸organisms of Corynebacterium kutscheri and treated with 5mg cortisone. After inoculation mice showed a marked loss of body weight and died in 5 to 10 days. The liver was enlarged remarkably with a number of abscesses and adhered with the neighbouring tissues. Occasionally, the spleen showed swelling with some nodular caseous foci. All lymph nodes in the peritoneal cavity were enlarged with abscesses and turbid ascites was seen in a few cases. Small abscesses were present also in the lung and kidneys of some cases, especially of those having survived for a long time after infection. There were calcified lesions and rarely purulent foci in the heart muscles and the pericardium. Organisms were detected from the liver of all cases examined after 2 days of infection, but in most cases the lung and kidney became positive only after 4 days of infection.

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Ear canker has occurred in many rabbits in a laboratory animal center for the past several years. Attempting to develop effective therapeutic and prophylactic measures, the present observation was conducted to identify mites causing the disease and to devise a very simple and rapid method for collecting them by the aid of adhesive vinyl tape from affected cymba conchae and basis conchae. The following results were obtained: (1) The mites collected were identified asPsoroptes cuniculi (Delafond 1958) . (2) Mites were demontrated by the mite adhering test in 20 rabbits showing no macroscopic signs of ear canker. (3) Of a total number of 216 rabbits examined 75 (34.7 %) were diagnosed as ear canker by this test and macroscopic observation.

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