ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 455 



modified and forms delicate and very high hypodermal cells, which, 

 gradually diminishing in width, project far into the interior of the 

 gill, unite with those of the opposite side and form a palisade-work 

 support. 



In Orchestia, further, ova appear to be developed in the "testes"; 

 the male organs generally resemble those of Gammarus, and form simple 

 tubes, consisting of a germ-gland and an efferent portion. The terminal 

 piece opens at the seventh segment into two short chitinous tubules, 

 which are the copulatory organs. There is a pretty large terminal 

 vesicle. Only the hinder half of the tubes produce male products, 

 the anterior quite constantly developing eggs, but for these there is 

 no special duct. The spermatogenous portion is lined by cylinder 

 epithelium, and aj)pears of considerable width ; the large cells with 

 coarsely granular plasma secrete an investment constituting the sper- 

 matophores ; in the median division of the cavity is the germinal 

 portion, consisting of a continuous plasmatic mass, in which are 

 imbedded spindle-shaped nuclei ; the plasma is finely granular, and 

 becomes aggregated around the nuclei to form well-marked cells, the 

 spermatoblasts. These undergo some changes before they pass out 

 to give rise to spermatozoa ; the nucleus grows to a great size, as 

 does also the nucleolus. 



The ovigerous portion has much the same histological structure ; 

 the spindle-shaped nuclei form cells, which dift'er in no respect from 

 the spermatoblasts, and they only are distinguished by developing 

 into ova ; as Nebeski justly points out, this resemblance affords a new 

 proof of the homology of the egg-cell and the spermatoblast. After 

 the growth of the nucleus, the j^lasma begins to dej)Osit yolk-material, 

 the egg increases in size, and gets a vitelline membrane. The eggs 

 developed in the male differ from those of the female in the structure 

 of their protoplasm, for the yolk-spheres are not in them so distinctly 

 developed, and it would appear that they never become fully matured. 

 This remarkable phenomenon has not, therefore, any physiological 

 significance, and "in structure the organ is truly a testis. The author 

 reminds us that Phalangium stands in a similar condition. 



In the sixth and last portion the author deals with the Crevettine 

 fauna of the Gulf of Trieste ; he describes as new Proholium terges- 

 tinum, and Dexamine doliclwnyx, and has notes on the rarer or more 

 difficult species. 



New Species of Entomostraca.* — Mr. V. T. Chambers records 

 these from the United States. 



Tacliidius (?) fonticola n. sp. is pale yellow, with the eye-spot 

 very large and bright crimson. The antennae of the female are short, 

 thick, and simple ; those of the male are 6-jointed ; the setaj of the 

 legs of the female are much shorter than those of the male. Length 

 of body, 0*385 mm.; of terminal setse, 0*3 mm. 



So far as is known, this species does not inhabit a portion of the 

 earth's surface more than two yards square. At the famous locality 

 known as Big Bone Springs, large "gums" (hollow trunks of trees) 



* Jouro. Cincinn. Soc. Nat. Hist., iv. (ISSl) pp. 47-8 (2 pis.). 



