170 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The six-footed larva is the primary larval type. Pantopods have little 

 to do with Arachnoids, but may be held to have arisen, along with 

 Crustaceans but on a different line, from a common Annelid stock. 



e. Crustacea. 



Effect of Sacculina on Host.* — Geoffrey Smith has enquired into 

 the precise action of Sacculina and Peltogaster on their hosts. They 

 feminize the males, converting them externally, and in part internally, 

 towards the female condition. They leave the female unchanged, or 

 hasten on the adult female characters, despite the partial destruction of 

 the starved ovary. The roots of the parasite affect the metabolism of 

 the crab just as an ovary does, by taking up fat and stimulating the 

 liver to make more. The glycogenic function is depressed, for there is 

 an absence of demand for glycogen, there being no growing or moulting 

 after the Sacculina has protruded. In the normal female the blood 

 becomes progressively charged with lutein and fat ; in the parasitized 

 crab this is not demonstrated, but the liver is always coloured with 

 lutein, and so are the Sacculina roots, showing that a transference of 

 these materials has occurred, perhaps so rapidly that their presence in 

 the blood cannot be detected. Smith's view is, in general, that the 

 parasite alters the composition of the blood to or towards a female 

 condition, and that this is naturally followed by the development of 

 female secondary characters or by the regeneration of an ovary instead 

 of a testis from the indifferent germ-cells that remain at the end of 

 infection. It is not the mere presence of fat in the blood that is the 

 cause of the transformation ; the fat is but the sign of more deep-seated 

 changes in the metabolism. In this case at least the author claims that 

 his theory of metabolic stimulation is superior to any hormone theory. 



Adaptations in G-alatheidea.t — K. Zimmermann compares three 

 types — Galathea squamifera, Porcellana platycheles, and Munida rugosa 

 — and indicates in an interesting way their special adaptations. A 

 description of the details of the structure of the branchial and other 

 organs serves to show how the animals secure steadiness in progression 

 or at rest within the wave-washed region of the shore, or are able to 

 guard against the choking of the branchial cavity and clogging of the 

 branchial organs by the mud of the low shore. 



Integument and Glands of Terrestrial Isopods.J — Werner Herold 

 describes the minute structure of the integument in Oniscus, Porcellio. 

 etc. He deals with the five strata, with the sculpturing, and with the 

 moulting. Particular attention is paid to the " white plates," which are 

 best seen on the first four thoracic segments, and the various kinds of 

 glands. He agrees with previous investigators that the " white plates " 

 represent secondarily acquired respiratory organs. A plate shows an 



* Quart. Journ. Micr. Sci., lix. (1913) pp. 267-95. 



t Journ. Marine Biol. Assoc, x. (1913) pp. 84-97 (4 pis. and 1 fig.). 



X Zool. Jahrb., xxxv. (1913) pp. 457-526 (3 pis. and 15 figs.). 



