1882.] 



,0n the Coxal Glands of Scorpio. 



97 



inconsistently remarks "each lobe when cut across is oval, with a 

 yellowish interior and a small central cavity." He states that the 

 gland is " dense thongh yielding, and on this account hard to be cut 

 with the microtome," and a.ppears to have confined his observations 

 accordingly to preparations of the fresh gland teased. Various kinds 

 of cells, from a "cortical" and a "medullary" substance of the 

 gland, are described and figured, but it does not seem to be possible 

 to bring these results of " teasing " into relation with what I have 

 observed in sections taken in various directions across the lobes of 

 the gland, and stained and mounted in the usual way in balsam. 



I find that each of the quadrilobate glands, which I should propose 

 to call the right and the left " coxal glands," is essentially a sac, lined 

 with a characteristic glandular epithelium, the lumen of the sac being 

 cut up into a number of inter-communicating passages by the pro- 

 duction of the inner surface of the sac into very numerous and far- 

 reaching trabecule. The gland-cells which clothe these trabeculee are 

 remarkable for their round, well-defined nuclei, and for the possession 

 of a peculiar differentiation of the substance of the cells near their 

 free surface, which has at first sight the appearance of a very thick 

 cuticle. 



A more detailed account of the structure of these cells may be 

 deferred for the present. My object now is to point out that in the 

 Scorpions there exists a similar pair of large coxal glands, having 

 essentially the same structure and position as the coxal glands of 

 Limulus. I was led to look for the existence of such glands by the 

 hypothesis that Scorpio and Limulus are very closely related members 

 of the class Arachnida; and it will, I think, be conceded that the 

 discovery of the existence of such corresponding organs goes a long 

 way towards confirming the conclusion as to the close affinity of the 

 two animals, to which I had been led by the observation in them of 

 numerous other structural coincidences. 



The coxal glands of the Scorpions are very large and prominent 

 structures, each attaining the size of a dried pea in a large Indian 

 scorpion of five inches in length. They are placed as in Limulus at 

 the junction of the coxae of the ambulatory limbs with the body 

 (fig. 1. B.). They do not send lobes forward corresponding to the 

 second, third, and fourth of the six limbs of the prosoma, but are 

 oblong white bodies resting upon the sternal prolongations of the 

 hinder limbs (fifth and sixth) on each side. Posteriorly each gland 

 rests against the ingrowing chitinous wall (fig. 1. C.) of the coxa of the 

 last limb of the prosoma which forms the posterior cornu of the 

 entosternite, but the mass of the gland lies in the hollow of the sternal 

 prolongation of the fifth limb, and is attached to it by a triangular 

 outgrowth which I shall provisionally speak of as a duct, though I 

 have not at present succeeded in finding any external aperture corre- 



vol. XXXIY. H 



