76 TRANSACTIONS OF THE [jAN. 11, 



of the Rectus abdominalis, the occurrence of a well developed 

 supra costalis, the union of Levator scapulse and Serratus mag- 

 nus, the thoracic extension of the scalenus group, interlocking 

 both with the Serratus and Obliquus externus. 



The aponeurosis of the Obliquus externus presents a well de- 

 veloped divisian of the internal pillar of the external abdominal 

 ring, dovetailing with the one from the opposite side and form- 

 ing the triangular ligament of the same. 



Mr. H. E. Crampton, Jr., reported some of his " Observations 

 upon Fertilization in Gasteropods." 



The observations were made upon the eggs of a species of 

 Doris, collected last summer on the Pacific Coast by Mr. Cal- 

 kins, and upon a species of Bulla, which deposited eggs at 

 Wood's Holl during the months of August and September. The 

 results may best be summarized by stating that a complete con- 

 firmation was obtained of the accounts of fertilization given by 

 Wilson and Matthews, Boveria ; Hill, for sea-urchins ; Meade, on 

 Chetopterus, Kostanecki and Wiejyewski, upon Physa, etc. The 

 sperm nucleus is preceded by the divided centrosome, an aster, 

 however, not being found till the union of the germ-nuclei. The 

 first polar spindle lies at each pole a double centrosome, the 

 second maturation spindle but one. These are of great size, 

 however, and the one remaining in the egg finally disintegrates, 

 the eentrosomes of the first cleavage spindle being derived from 

 the sperm. The germ-nuclei do not fuse, but lie very close to 

 one another, in contact. 



Mr. N. R. Harrington gave an account of the life history of 

 Entoconcha, a mollusc parasitic in a Holothurian. His paper 

 was illustrated by photographs. 



The following paper was read by title : N. R. Harrington and 

 B. B. Griffin, " Notes on the Distribution, Habits and Habitat 

 of some Puget Sound Invertebrates." The paper appears on a 

 later page. 



C. L. Bristol, 



Secretary. 



