ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 243 



Onisci, Ligia9, Tylides, and Syspastidre. In the first there are fourteen 

 genera, three of which {Eubelum, Cylloma, and Scleropades) are new ; 

 in the second, four are described, and the remaining two contain each 

 a genus. The total number of species described is 404 or 410, of 

 which 312 or 316 are good species, and 92 or 94 are unknown to the 

 author or are reported species. 



Gammarus pulex var. subterraneus.* — Dr. E. Schneider gives 

 an account of the subterranean variety of Gammarus pulex which is 

 found at Clausthal. The first point of interest is its pale colour, 

 pigment being so completely absent from its body that it is milk- 

 white and transparent ; even the fat-cells, which are intensely red or 

 orange-yellow in the ordinary G. pulex, are quite white. In the 

 second place the eye is not normally developed, but is in the first 

 stage of reduction ; the crystalline cones show signs of degeneration, 

 and the whole eye exhibits that " megalophthalmy " or proportionately 

 greater size which is so often the first indications of loss. The 

 pigment has also begun to be reduced, and is of a dirty black, instead 

 of a brownish colour. The anterior pair of antennae exhibit elonga- 

 tion, owing to the increase in the number of the joints. 



There is, as compared with the ordinary forms, a considerable 

 increase in the amount of calcareous deposits ; and there is always a 

 considerable amount of iron-oxide in the contents of the intestine, 

 whence the iron makes its way to various parts of the body. 



Anatomy of Chloremians.t — Some points in the anatomy of 

 Siphonostoma dipTiochaetos are described by M. E. Jourdain. 



There are two varieties of peculiar papillas in the network of the 

 mucous tube, attached to the body by long peduncles. One variety 

 consists of a mass of glandular cells. The second kind are fusiform, 

 accompany the setae, and consist of ciliated cells ; there are tactile 

 organs. He considers as a vascular organ the " problematic organ " 

 of Horst.| This consists of a peculiar dorsal caecum of the alimentary 

 tract, the glandular lining of which is continued into it, whilst its walls 

 are transformed into a great blood sinus ; its rhythmical contractions 

 suggested to him its circulatory functions. 



Nervous System of Peltogaster.§— M. Y. Delage describes the 

 central nervous organ of Peltogaster as consisting, like that of 

 SaccuUna, of a single ganglion ; it is placed within the mesentery 

 which connects the cloaca with the pedicle, and almost between the 

 two cement-glands ; it is only separated from the exterior by half the 

 thickness of the mantle. It is elongated in form, and about 1/10 mm. 

 in size; it is really simple, that is, does not consist of two fused 

 halves; it contains small fusiform peripheral and large multipolar 

 central cells ; it gives off a number of very fine nerves, the distribution 

 of some of which is described. 



Peltogaster may be regarded as being derived from SaccuUna, and 



* SB. Akad. Wiss. Berlin, 1885, pp. 1087-1104 (1 pi.). 



t Comptes Eendus, cii. (1886) pp. 270-2. 



i See this Journal, v. (1885) p. 457. 



§ Comptes Kendus, c. (1885) pp. 1010-2. 



B 2 



