THE NAUTILUS. 123 



P, (Syrnola t) wtnkleyi, Is described from Branford, Conn. Turbo- 

 nilla is divided into five subgenera Ptycheuliuiella, Chemnitzia, 

 Turbonilla, Strict urbonilla and Fyrgiscus. A new subspecies, T. 

 (Strioturbonilla) busfnana abyssicola, is described from 1290-1.537 

 fathoms off Martha's Vineyard. T. verrillt, vinece, branfordensis, 

 buteonis, winkleyi, senilis, sumneri, cascoensis, whiteavesi and edward- 

 ensis of the submenus Pyrgiseus are described as new; the last two are 

 from Prince Edward Island. T. mighelsi is proposed for T. costu- 

 lata Verr. 1873 (non Risso 1826). Under Odostomia six subgenera 

 are recognized Cbrysallida, Evalina, lolaea, Menestho, Odostomia 

 and Liostomia. The following are new : 0. ( Chrysallida] bushiana 

 and willisf, 0. (Evalina) winkleyi, 0. (lolaea) hendersoni, 0. {Men- 

 est/to') tnfida bedequrnsis and bisuturalis orilensis. 0. morseana is 

 proposed in place of 0. sufcnta Verr. 1880 (non A. Adams 1860). 

 The Pyramis striatula Couthouy forms the type of a new genu8, 



Couthouyella. There are excellent figures of nearly all the species 



C. W. J. 



NATURAL HISTORY, ORGANIZATION AND LATE DEVELOPMENT 

 OF THE TEREDINID.E OR SHIP- WORMS. By Charles P. Sigerfoos. 

 (Bulletin of the Bureau of Fisheries, xxvii, pp. 193-231, pi. vii- 

 yxi.) Xylotrya gouldi, Teredo dilatata and 7. navalis from Beaufort, 

 N. C., have been investigated. T. navalis carries the eggs in the 

 gills, but in the other species they are laid free into and fertilized in 

 the water. In one case T. dilatata was estimated to produce one 

 hundred million eggs. The egg develops into a typical small bivalve 

 having a swimming organ (velum). Throughout the summer these 

 may be found crawling over wooden structures in search of favorable 

 crevices for attachment. Once attached by a single long byssus 

 thread, the larva loses the velum, scrapes away the surface of the 

 wood with the ventral edges of the shell-valves, and the loot develops 

 into a pestle-shaped organ which assists the shell in burrowing. On 

 the external surface of the valves at the anterior edges is formed the 

 first row of small teeth, which at this and later stages are the 

 mechanical agents by which the animal bores into the wood. This 

 transformation has taken place within two days from the time the 

 larva has settled, and afterwards the animal rapidly becomes an 

 elongate ship-worm. Evidence is given showing that the ship-worm 

 may reach a length of 4 feet and diameter of 1 inch in about one 

 year. The sexes are separate in adult ship-worms, but young indi- 

 viduals of X. gouldi are frequently hermaphroditic, in which case the 

 male cells develop first. The anatomy is very fully described and 

 illustrated. This timely paper, a valuable addition to our knowl- 

 edge of Pelecypod morphology, can be obtained of the Bureau of 

 Fisheries. H. A. P. 



