48 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Structure of Male in Genus Cambarus.*— J. Arthur Harris discusses 

 the "dimorphism" which has been described in the males of the species 

 of this genus. He has been able in the first place to entirely confirm 

 Faxon's statement that the two forms alternate in the life-history of the 

 individual. Of the two forms, the first is definitely male and capable of 

 copulation, while the second approaches the female in type, and from 

 the shape of the copulatory abdominal appendages is probably incapable 

 of sexual union. In C. immunis the animals emerge from their winter 

 burrows in the first form, and retain this form till about the end of April 

 when they moult and appear in the second form. The length of time 

 during which this form is retained is not perfectly definite, but in the 

 late summer and in autumn another moult occurs, and the first form re- 

 appears. To these statements there are, however, exceptions, the regular 

 alternation being absent in some adult individuals. No very marked 

 differences could be made out between the testes of the two forms, but 

 the author is on the whole disposed to believe that the greater part of 

 the regeneration of the sexual elements takes place during the period in 

 which the body has the second form. 



New Blind Crustacea, f — 0. A. Sayce records the very interesting 

 discovery of three new Crustacea from the same fresh-water runlet in 

 the district of Gippsland, Victoria, Australia, which, though not closely 

 allied, resemble one another in the absence of eyes. The streamlet is in 

 a densely wooded region in which the thick undergrowth largely shuts 

 out the direct rays of the sun but, in addition to the blind forms, con- 

 tains numerous specimens of a crayfish (Astacopsis) and an Amphipod 

 (Atyloides), both of which have normal eyes and occur elsewhere. The 

 new forms are two Isopods, not nearly related (Phreatokoides gracilis 

 and Janirella pusilla), and an Amphipod (Nipliargus pulcliellus), all of 

 which have been described by the author elsewhere. All are perfectly 

 blind, are of a uniform white or pale yellow colour, and appear, as con- 

 trasted with related forms, to have the antennas elongated. Except in 

 Janirella the body further appears to be remarkably slender, a common 

 character in subterranean forms. The interesting point is that the author 

 was not able to find any subterranean waters in the locality, and the 

 geological characteristics of the district appear to negative the idea that 

 any large caves can occur in the district. 



Annulata. 



Seasonal Histolysis in Polychaets.^;— G. Bohn describes some of the 

 autumnal troubles of Arenicola and Pectinaria, such as disappearance of 

 gills and perforations of the skin. There seems to be a seasonal 

 histolysis, and the author believes that one of the determining conditions 

 is an " alkaline intoxication " due to red Algae, such as Ploeamium 

 coccineum, and this seems to have for its consequence an absorption of 

 carbonic acid on the part of the animal. [Here the author's physiology 

 seems to us somewhat elliptical.] 



" The histolytic changes exhibited by Annelids in autumn, and 



i * Zool. Anzeig., xxiv. (1901) pp. 683-9. 

 t Ann. Ma<:. Nat. Hist., viii. (1901) pp. 558-64. 

 J Coruptcs Eendus, cxxxiii. (1901) pp. 646-8. 



