298 SUMMARY OF CURRENT RESEARCHES RELATING TO 



New Parasitic Copepod.* — W. Harold Leigli-Sharpe describes 

 Lernxopoda scyllicola sp. n., the females of which occur fixed by the 

 second maxillae just outside the cloaca of dogfish {Scyllium canicula), 

 especially on male specimens, where they may also occur on the claspers. 

 The ends of the second maxillae are swollen, as long as the trunk, and 

 united to a bulla of characteristic shape. The thorax alone shows 

 traces of segmentation. The mandibles are slender and aciculate, and 

 the maxillipede has a slender terminal joint and a peculiar hook-like 

 projection on the basal joint between the cushions of spines. 



New LernaeopodidsB.t — C. B. Wilson describes no fewer than twelve 

 new genera of these curious Copepod parasites, and gives a revision of 

 the entire family. A very useful account is given of the general 

 structure and development of Lernaeopods. In regard to the question 

 of the pigmy male's nutrition, it is pointed out that the adult has 

 mandibles as large and powerful as those of the female, and a well- 

 developed oesophagus and stomach, but apparently no mouth or anus. 

 The stomach is lined with large gland cells, but there are no separate 

 digestive glands. The excretory organs are exceptionally large and 

 have well-developed ducts. The male was never found except on the 

 female. It is unUkely that the male lives long after fastening the large 

 spermatophores to the sexual aperture of the female. Both sexes go 

 without food during the free-swimming period, for their mouth parts 

 are only suited for obtaining food parasitically. During the second 

 Copepodid stage they both suck the blood of the fish. But it is 

 improbable that the male gets any food after he passes from the gills 

 to the female. 



Thompsonia.^: — F. A. Potts describes forms of this extraordinary 

 Rhizocephaian genus, which he observed on two crabs ( Thalamita prymna 

 and Actsea ruppellii) and on an Alpheid {Synalpheus hrucei). A pre- 

 liminary paper was previously referred to.§ The parasite appears as 

 numerous external sacs on the host. The root system is continuous 

 throughout the body of the host, whatever the number or stage of 

 development of the external sacs may be. Where they penetrate the 

 appendages the roots contain fewer yolk globules, and the lacunar space 

 is filled with germ-cells. Besides the external sacs, there are a number 

 of terminal swellings in the tissue of the appendages. These are similar 

 in structure to the external sacs, and become external at a subsequent 

 moult of the host. The external sacs consist of a mantle with an 

 external and internal cuticular investment and a visceral mass mainlv 

 occupied by the ovary. No mantle cavity is found between the mantle 

 and visceral mass. 



There is no testis, and development is probably parthenogenetic. 

 The Qg^ is Hghtly yolked, and gastrulation takes place by epibole. The 

 Nauplius stage is omitted, the young being hatched at the Cypris stage, 



» Parasitology, viii. (1916) pp. 262-73 (6 figs.). 



t Proc. U.S. Nat. Museum, xlvii. (1915) pp. 565-729 (32 pis. and 15 figs.). 

 X Papers Dept. Mar. Biol. Carnegie Inst. Washington, viii. (1915) pp. 1-32 

 (2 pis. and 12 figs.). 



§ See this Journal, 1914, p. 351. 



