482 SUMMARY OF CURRENT RESEARCHES RELATING TO 



section of the mandibulate mouth is often a matter of considerable 

 difficulty. Discrepant opinions abound. He discusses the palpi of 

 Ischnocera and Amblycera, the oesophageal sclerites and glands, the 

 maxillary forks, and the like. 



In Dochophorus sphenophorus, from which, at first, the glands and 

 sclerite appeared to be absent, there is a hypopharynx exhibiting an 

 abrupt deviation from the normal form in the Ischnocera. Yet the 

 species is typical in external characters. The oesophageal sclerite is 

 probably present in all Mallophaga, and should prove to be of service in 

 breaking up many of the unwieldy genera, such as Docophorus and 

 Menopon. 



y. Myriopoda. 



Structure of Poison-gland of Scolopendra morsitans.* — E. Paw- 

 lowsky finds that the poison-gland occurs in the basal joint as well as in 

 the claw of the maxillipede, and that it has no defined efferent duct 

 since the body of the gland is directly coalescent with the hypodermis. A 

 perforated chitinous tubule traverses the gland and opens on the 

 integument near the tip. This serves as a duct. The gland is com- 

 posed of a very large number of epithelial-muscle-capsules in which the 

 glandular cells lie. When there is strong secretion the walls of these 

 capsules burst and the contained secreted substance unites into one 

 mass. The tracheae which enter the gland run inside the walls of the 

 epithelial-muscle-capsules and never pass into the lumen or into the 

 glandular cells. There is a complete homology between the elements of 

 the gland and those of the integument. 



e. Crustacea. 



Structure of Blind Prawn of the Lake of Tiberias.t — Eken- 

 dranath Ghosh points out that this prawn, Typhlocaris galilaea Caiman, 

 resembles Palsemon in most respects, but exhibits certain differences in 

 the vascular, alimentary, and genital systems. The most remarkable 

 feature is the degenerate condition of the eyes, the external parts of 

 which have totally disappeared, although the optic peduncles are well 

 developed. The optic ganglion persists, although there is no trace of 

 retinal structures, and the optic nerve is much reduced, and apparently 

 does not reach the ganghon. The nerve to the first antenna is pecu- 

 liarly stout. Dr. Nelson Annandale notes that there is no evidence 

 that the animal now lives underground, though it has all the characters 

 of a cavernicolous or subterranean form. It may be seen moving about 

 in the open at midday. 



Structure of Land Crayfishes. J — Gr. W. Smith and E. H. J. 

 Schuster describe the peculiarities of the species of Engaeus which 

 burrow in damp ground. The great hairiness of the mouth-parts and 

 neighbouring regions may be correlated with the need for filtering the 

 muddy water in the burrows. But most of the peculiarities are of the 



* Zool. Jahrb., xxxvi. (1913) pp. 91-112 (2 pis.). 



t R6sum6s des Communications, 9e Congres Internat. Zool. Monaco, 1913, 

 ser. 3, pp. 5-6. % Proc. Zool. Soc, 1913, pp. 112-27 (14 pis.). 



