INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 719 



Generative Organs. — Unlike what obtains in the Gammarida, the 

 ovaries of Phronima and its allies are placed very far forwards in the 

 body ; flattened in form, and pointed at either end, they are provided 

 with a thick structureless wall, supporting a well-nucleated epithe- 

 lium. The ova form a single layer. The bent terminal portion of 

 the oviduct widens out into a seminal pouch. In the young males the 

 sperm-producing gland, and the duct which contains the spermato- 

 phores, are not distinctly seiiarated, but this is the case also in the 

 adult, between which and the young the chief difference is that the 

 seminal duct of the former is longer, and contains two mature sperma- 

 tophores. The paper is illustrated by eight plates, containing 

 seventy figures. 



Glands found in the Appendages of the Phronimida.*— Paul 



Mayer, in dealing with these glands, of which, so far as he knows, 

 Professor Claus has alone made mention, points out that the sixth 

 and seventh pairs of thoracic appendages are distinguished by their 

 form and size from those in front of them ; this is due to the presence, 

 in their basal joints, of large glandular masses, which, if present in 

 the more anterior legs, are but feebly developed. Placed in the wall 

 of partition formed by the membrane which separates the arterial 

 from the venous stream of blood, the glands aj)pear to be formed by 

 the predominant growth of some of the cells in this region, and to 

 form groups of three or five. As to their function, it is impossible to 

 offer anything more than supposition ; at first the author supposed 

 that they might be phosphorescent, but further observation did not 

 confirm this view ; their relation to the blood-stream suggests that 

 they are excretory in function ; or, again, tliey may be poison-glands. 

 It is pointed out that in the Hyperida these glands are better de- 

 veloped than in the Phronimida, but they are not so regularly 

 arranged. 



"House" of the Phronimida.t — In his next " Carcinological 

 Study " Mayer confirms the view of Claus that Phronima very gene- 

 rally makes a home for itself in Pyrosoma. On November 27th, 1877, 

 the author took a fairly well-developed female from a house, which, 

 on account of its thin, soft walls and i)eculiar ai:)pendage, he can only 

 regard as being one of the Salpidaj. On the 25th of December he 

 took a breeding female from its Pyrosoma habitation, and placed it in 

 a glass with a specimen of Ahyla pentagona ; this was shortly seized on, 

 and in some ten minutes its velum was eaten up ; in a short quarter 

 of an hour the crustacean entered on its new home. On the morning 

 of the 26th the polyps had disappeared (? were eaten), and the home 

 took on the characteristic shape, with orifices at either end. On the 

 morning of the 27th the Phronima was removed from the Hydroid, 

 and placed under the same conditions with a specimen of (Sa/pa 

 fusiformis ; this was in like manner attacked, and on the morning of 

 the 28th the nucleus itself of the Salpa had disappeared. Some hours 

 later the invader was removed from its new home and replaced in its 



* 'Mitth. Zool. Stat. Neapel,' i. (1878) p. 40. 

 t Ibid., p. 4G. 



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