68 SUMMARY OP CURRENT RESEARCHES RELATING TO 



H. L. Osborn regards this as probably a pathological condition, which, 

 however, does not prevent normal development. About two days after 

 fertilization a protoplasmic cap appears at one pole ; though it stained 

 deeply, it was structureless ; in a surface view this has the appearance 

 of a dark pit. Its relation to future changes is unknown. It, however, 

 disappears, and a white mound makes its appearance on the surface — 

 the " primitive cumulus " — but its relation to past and future changes 

 is unknown. The next thing observed was a semicircular depression, 

 between the limbs, of which three pairs of buds appear in succession ; 

 these are the three anterior pairs of appendages. The mouth is an 

 elongated antero-posterior slit, in front of the first pair of limbs. All 

 these structures are situated on an oval area, marked off from the rest 

 of the egg. The anus is not yet formed. The remaining pairs of 

 appendages appear in succession, as well as the ventral nervous 

 system, which appears as a thickening along the ventral mid-line. 

 He contradicts Packard and agrees with Dohrn as to the position of 

 the compound eyes ; they appear on the fourth somite. 



Chemical Composition and the Coagulation of the Blood of 

 Limulus, Callinectes, and Cucumaria.* — Dr. W. H. Howell describes 

 the bluish coloration of the blood of Limulus after exposure to the 

 air. The blood clots immediately, but never forms a solid mass. 

 Coagulation could not be prevented by the usual methods. It shows 

 the presence of four albumens, the highest of which is exceedingly 

 difficult to precipitate. He describes the actions of various reagents, 

 and concludes that the albumens are related to paraglobulin. The 

 blue colour of the serum is due to a compound of copper with 

 albumen. The fibrin of the clot is formed by the corpuscles. 



In Callinectes, the serum contains two albumens, and is similar 

 to that of Limulus. 



The red corpuscles in the perivisceral fluid of Cucumaria contains 

 hemoglobin: coagulation results from the fusion of the white cor- 

 puscles which entrap the red ones. Thus the coagulation of the 

 blood of these forms is similar to that in the Mammalia, as is also 

 the fibrin. 



Coxal Gland of Limulus and other Arachnida.f — Mr. G. L. 



Gulland brings forward evidence in favour of the view that the coxal 

 gland of Limulus and other Arachnida is a modified nephridium. In 

 a note, Prof. E. Eay Lankester thinks that the facts of the young 

 Limulus having the gland in the form of a tube opening to the ex- 

 terior by one extremity, and to the primitive coelom by the other, and 

 of its being a paired organ belonging to a single segment, make clear 

 that it has the essential anatomical features of a " nephridium " ; its 

 conversion into a ductless gland of the adult is paralleled by the 

 history of the suprarenal body of vertebrates, to which it is, apparently, 

 similar, both morphologically and physiologically. Prof. Lankester 

 reminds us of the correspondence seen in the case of the " shell- 

 gland" of Entomostraca, and puts forward the hypothesis that the 



* Johns-Hopkins Univ. Giro., v. (1885) pp. 4, 5. 



t Quart. Journ. Mior. Sci., xxv. (1885) pp. 511-20 (1 pi.). 



