ZOOLOGY AND BOTANY^ MIOROSOOPY, ETC. 49 



the same way that leaves do, investigated two species, Siphonophora 

 malvcB and S. rosce, with a view of ascertaining whether they contained 

 chlorophyll ; he discovered by applying the usual tests that chloro- 

 phyll was undoubtedly present ; the objection that this substance is 

 absorbed from plants by the insects and not elaborated in their own 

 bodies, is met by the statement that it is also to be found in those 

 species that live upon the coloured petals of flowers. The con- 

 clusion arrived at needs to be confirmed " by a more matured study," 

 and M. Macchiati promises a fuller investigation of this interesting 

 discovery. 



y. Arachnida. 



Testis of Limulus.* — W. B. S. Benham describes the testis of 

 Limulus. The organ consists of two lateral and a median network 

 formed by ramifications and anastomoses of the vasa deferentia ; on 

 the walls of these ducts are situated the sperm-sacs, sometimes singly 

 but more usually in groups ; in the latter case the sacs communicate 

 with each other and only one opens directly into the duct ; the sacs 

 contain groups of spermatozoa without tails, the latter being apparently 

 developed within the ducts themselves ; occasionally the sperm-sacs 

 were situated at some distance from the ducts and no ductule could 

 be traced from them ; it is possible therefore that they are not formed 

 as diverticula of the spermatic duct, but originate independently, and 

 only acquire a secondary connection with it. The chief point that is 

 dwelt upon in the paper is the branching and anastomoses of the 

 spermatic duct ; this fact lends strong support to Lankester's views 

 concerning the close relationship between the Arachnida and Limulus ; 

 for in no crustacean is there any such network formed by the 

 spermatic duct, whereas it is a constant character of the Arachnida. 



Polymorphism of Sarcoptidae.t— E. L. Trouessart and P. Megnin 

 have a note on the sexual and larval polymorphism of the plumi- 

 colous Sarcoptidse. The species belong to the subfamily Analgesince 

 which is divisible into the three groups of Pterolychece, Analgesece, and 

 Proctophyllodece ; in the two former the fecundated females, after their 

 last ecdysis, have the abdomen entire and not lobed, but in the third 

 the adult females have, at the end of the abdomen, two conical 

 chitinous prolongations ; a study of exotic forms shows that in 

 nymphs and larvae the abdomen is bifid. In one preparation, the 

 male, even after the development of its generative organs, was seen 

 inclosed in the transparent integument of the nymph with a forked 

 abdomen ; this, according to ordinarily received ideas, would lead us 

 to think that the male emerged from the skin of a female. 



The form, therefore, with a forked abdomen, is not sexual but 

 larval, and we have here only another example of the law that female 

 Sarcoptidse retain more or less the form of the nymph, while the males 

 take on a different appearance. 



A still more remarkable polymorphism was observed in the males 



* Trans. Linn. Soc— Zool., ii. (1883) p-^. 363-6. 

 t Comptes Rendus, xcvii. (1883) pp. 1319-21. 

 Ser. 2.— Vol. IV. E 



