101 Transactions of the 



III. — Further Notes ox, the Zoosperms of Crustacea and other 

 Invertebrata. By Alfred Sanders, Lecturer on Comparative 

 Anatomy at the London Hospital Medical College. 



{Read hcfui'e t)ie Eoyal MicroscopicaI; Society, J<ni. 7, 1874.) 

 Lower portion of Plate LIV. and Plate LV. 



Since writing my last paper * on this subject, I have not failed as 

 opportunity offered to examine the zoosperms of various inverte- 

 brata, and more especially those of Crustacea ; the result has been to 

 confirm the conclusions at which I then arrived, and to bring to 

 light many kinds of ssoosperms as they vary in detail in different 

 species. The genus Pagurus seems to offer a great variety of forms, 

 every species as far as I have examined them differing from every 

 other in the proportion of the caput to the rays, or of the latter to 

 the tail, or again in the shape of the head. 



In Pagurus maculatus (Fig. 1) the zoosperms have a more elegant 

 shape than in P. Bernhardus. The contour of the head is concavo- 

 convex ; swelling out at the base it becomes concave as it contracts 

 towards the point. When they are viewed from above the outline is 

 seen to be circular. It appears that the cortical part is composed of 

 a different material from the centre, for on the application of sea- 

 water the latter portion is entirely forced out and destroyed, leaving 

 only the outer shell. The rays are three in number ; they are flex- 



EXPLANATION OF LOWER PART OF PLATE LIV. and PLATE LV. 



. Plate LIV. 



Fig. 1. — Zoospeims of P. maoulatus ; a, biile view; b, top view ; X 600. 

 „ 2. — Zoosperms of F. maculatus not quite mature x 600. 

 „ 2 a. — Larger cells from the testis of P. maculatus x 300. 

 „ 3. — Zoosperms of P. callidus x 600. 

 „ 4. — Zoosperms of P. ornat'is x 600. 



Plate LV, 



5 a. — Smaller particles of protoplasm from testis of Porcellana plntychelcs. 

 5 6. — The line dividing the same into two unequal parts. 

 5 c. — Smaller section beginning to bud out in three stages. 



5 d. — Mature zoosperms ; all about x 770. 



6 a. — Spermatophore, front view, of P. platijcheles. 

 6 6. — Portion of the basal ribbon. 

 7. — Zoosperms of Galathcea sqnammifera x 770. 

 8. — Zoosperms of Palemon squilla x 700. 

 9. — Zoosperms of L'peira diadcma x about 900. 



10. — Zoosperms of Phdangium cornutmn x 600. 

 11. — Zoosjjerms oi Astcropectcn crenastcr X 600. 

 12. — Zoosperms of Holothuria tuhulos i x 600. 



12 a. — The capita of the zoosperms of H. tnhulosn after they have imbibed 

 sea-water x 600. 

 „ 13. — Zoospurius of Aphrodite sp. ? x 600. 



'M. M. J.,' May, 1869. 



