RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 121 



between the 24th and 25th segments. Moquin Tandon (Monog. 

 Hirud., 1846, 326) likewise assigns the latter as the position of the 

 male aperture in the genus Hirudo. 



The position of the generative apertures in H. decora often appear 

 more or less discolored or of a dull purplish hue, and the same is 

 the case with the group of papillae back of them. The latter do 

 not exist in the medicinal leech of Europe. The}- are quite con- 

 spicuous in ours. I ha\e suspected that they were provided for 

 the adherence of individuals in sexual intercourse, and this view is 

 confirmed by Mr. S. J. Moore, the well known professional leecher 

 and bleeder of this city. Mr. Moore informs me that in copulo two 

 individuals adhere in the position of the papillae and make two turns 

 of a spiral upon each other. 



The red and black spots of the back contain from 20 to 22 in each 

 row. 



Length up to 7 inches by 8 lines in breadth posteriorly, and the 

 acetabulum 3 lines in diameter. 



[October, 1868.] 



Prof. Leidy directed attention to a specimen of a sponge which 

 had been for man}- years in the Museum of the Academy and had 

 been presented by the late Dr. R. E. Griffith, who obtained it in 

 the Island of Santa Cruz, W. I. It is especially interesting from 

 its relationship with that most beautiful of all known sponges, the 

 Eupledella aspergillnni, and apparently also to that enigmatic bod}', 

 the Hyalonema Sieboldii of Japan. vSpecimens of both these were 

 also exhibited ; a beautiful one of the former, from the Philip- 

 pines, presented to the Academy by Joseph Henry Craven. Sev- 

 eral specimens of the Hyalonema. presented by Drs. Ruschenberger 

 and Sinclair, consist of a twisted fasciculus or rope of long, coarse, 

 translucent siliceous threads, partially twisted with a brown verru- 

 cose membrane or bark. When the first specimen was presented 

 to the Academy, in i860 (Pr. A. N. S., i860, 85), Prof. Leidy, as 

 curator, reported it as a part of a sponge with a parasitic polyp upon 

 it. One of the specimens may have some significance as to the rela- 

 tion of the rope of spicules and its polyp covering. It has attached 

 two shark eggs and part of the tendril-like cords of another. The 

 tendrils clasp the rope, and are also partly invested with the polyp 

 crust. In the complete condition the Hyalonema fasciculus appears 

 always to be associated at one end with a sponge mass. Originally 

 described by Dr. R. E. Gray, the fasciculus was viewed as the 

 axis of a coral, of which the verruco.se bark formed part, the warts 



