ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ' 375 



y. Arachnida. 



Skeletotrophic Tissues and Coxal Glands of Limulus, Scorpio, 

 and Mygale.* — E. Eay Lankester points out the necessity for a 

 detailed and compreliensive study of the connective and other tissues 

 of the skeletotrophic group in both Arthropoda and MoUusca 

 " before we can pretend to offer any satisfactory account of the vas- 

 cular system in those groups, and of the ' lacunar ' connection between 

 arteries and veins, which is confidently described and discussed by all 

 zoologists, but has never yet been demonstrated to exist in a manner 

 satisfying the requirements of modern histology." 



In the account of the structure of the entosternites, the author 

 says that it seems possible to morphologically define " cartilage " by 

 the isolation of each one of its constituent cells in a firm matrix, and 

 by the triaxial multiplication of those cells, whether the matrix be 

 homogeneous, fibrillated, or penetrated by reticular condensations. 

 A well-marked entosternite has for the first time been found among 

 the Crustacea, and, curiously enough, in the most archaic form, Apus. 

 After a careful description of the various forms of connective tissue 

 the author passes to the blood-corpuscles of Limulus and Scorpio, 

 which agree remarkably in form, size, and granulation ; both contain 

 a large quantity of heemocyanin, and are both, in bulk, of a deep 

 indigo-blue colour. 



The coxal glands are next dealt with; their minute structure 

 points to their forming an active secretory apparatus, the materials 

 for which are brought to them by the intercsecal tissue ; they may 

 well be compared with the green glands (antennary coxal glands) of 

 the Decapod Crustacea, from which, however, they differ in having 

 no definite outlet, and in the structure of the epithelial cells. The 

 author justly points to the occurrence of " these glands in their cha- 

 racteristic position, and with their characteristic corticated secretory 

 cells in lAmulus on the one hand, and in Scorpio and Mygale on the 

 other," as another argument in favour of that classificatory alliance 

 of Limulus with the Arachnida, of which he has, in earlier essays, 

 afforded so many instructive demonstrations, 



8. Crustacea. 



Liver of Decapods.t — J- Frenzel gives a short account of the 

 results of his investigation of the gland of the mid-gut, or liver, 

 of twenty-six species of Decapods. The epithelium of this gland 

 consists of fat-cells and ferment-cells ; the size of them does not 

 seem to differ with that of the individual, but to be pretty constant 

 in each species. In Carcinus they are • 07 mm. and in Palinurus 

 •06 mm. in diameter. In section, each tube of the gland is seen to 

 be invested by a delicate fringe, which is more or less distinctly 

 striated, and which has the function of a porous cuticle. The longi- 

 tudinal striation seen in the upper part of the cells calls to mind 

 that which obtains in the cells of the mid-gut of insects and 



* Quart. Jouru. Micr. Sci., xxiv. (1884) pp. 129-62 (7 pis.), 

 t SB. K. Akad. Wiss. Berlin, xlii. (1883) pp. 1113-9. 



