ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 217 



Two New Genera of Epicarida.* — MM. A. Giard and J. Bonnier 

 have found new forms of these Bopyridae, parasitic on specimens 

 of Palsemon brought from the fresh waters of Dutch Malaysia, and pro- 

 bably from the island of Amboyna. That which Semper named Bopyrus 

 ascendens they call Probopyrus ascendens, and the other Palegyge Borrei. 

 The foi-mer is distinguished from Bopyrus by the characters of the pleon 

 in both sexes ; that of the female has appendages which appear to have 

 escaped the notice of Semper, and that of the male has traces of the 

 lateral appendages which are completely wanting in Bopyrus. 



Palegyge bears to Gyge the same relation that Probopyrus has to 

 Bopyrus, for they represent a less degraded form which has retained the 

 typical Ionid structure of the pleon. 



An interesting parallelism may be drawn between the pbylogenetically 

 archaic nature of the parasites and their hosts, for Palsemon dispar and 

 P. ornatus are older than P. serratus, P. squilla, and others on which 

 Bopyrus is parasitic; the older forms have survived, owing to their 

 inhabiting fresh or brackish water. 



Lernaeascus and the Philichthydse.f — Prof. C. Claus has been able 

 to make a more complete study of the little parasitic Crustacean which 

 is found on the skin of Solea monochir, which he named Lernseascus 

 nematoxys. He gives a detailed account of the male, of the young stage, 

 and of the mature female. He also describes the female forms of the 

 allied Philichthys and Sphserifer. On Lernseascus he notes the presenco 

 of 50-60 pairs of dorsal and ventral scale-like structures or cuticular 

 thickenings which appear to serve as delicate locomotor organs. 



Without attempting to summarize the exact results of Claus's anato- 

 mical investigations, we shall quote his diagnosis of the family to which 

 he refers Lernseascus and its allies. The Philichthydae are completely or 

 almost completely segmented parasitic Crustaceans, with only two pairs 

 of copepod appendages modified as organs of attachment, and with a 

 rudimentary third pair. The male, like that of the Lernaaae, is small, 

 with normal, distinct, segmentation, with an eye divided into three, with 

 two pairs of antennas and maxillae on the head, and with dorsal integu- 

 mentary appendages on the second thoracic segment. The fourth and 

 fifth segments of the thorax are without appendages. The two testes 

 are shifted to the terminal portion of the abdomen. The female, like 

 that of a Lernaea, is large out of proportion, usually with indistinct 

 segmentation, with an eye in three portions (if it be always present), 

 with an enlarged second and third thoracic segment, which, by them- 

 selves, or plus the next segment, are fused in a distended portion. On 

 this, and on the head, as also on the genital and terminal segments, 

 there often arise, as in many Ohondracanthae, paired outgrowths. The 

 feeling antennae always remain separate. The attaching antennae 

 may be degenerate. The mouth-area with the maxillae is very definitely 

 circumscribed, and surrounded by a wide short tube. The two double- 

 branched and the third simple pair of appendages are minute and 

 rudimentary. The receptaculum and genital apertures are dorsal. 

 Both sexes live in mucous canals of the fish skin. Prof. Claus then 

 diagnoses the separate genera Philichthys, Sphserifer, Leposphilus, 

 Lernseascus. In Sphserifer, only the females are known. 



* Comptes Rendus, cvi. (1888) pp. 304-6. 



t Arbeit. Zool. Inst. Wien, vii. (1887) pp. 281-315 (4 pis.). 



