270 MENSCH. [Vol. XVI. 



dredgings in and about Vineyard Sound. They occur most 

 abundantly among the stems of Parypha, and during certain 

 seasons of the year may be obtained in all stages of develop- 

 ment by placing the hydroids in vessels of water and allowing 

 them to remain until the water begins to become stagnant, 

 when the specimens will collect at the surface or sides of the 

 vessel. The mature sexual individuals are best collected in the 

 tow-net at night in the region of piles, though they may also 

 be found among the hydroid stems. 



The abundance of the stolon-bearing forms is very much 

 dependent upon the condition of Parypha, being most plentiful 

 when the hydroids are fully developed, and disappearing almost 

 altogether at the time when the hydroids die down. Occasional 

 specimens in different stages of stoldnization may also be found 

 among the stems of Bugula and certain algae, but never in any 

 number, even in localities otherwise favorable to their exist- 

 ence. In dredgings of loose sand, taken from a depth of from 

 five to ten fathoms, quite a number of specimens were also 

 obtained. 



Associated with this species may be found two other species 

 of the tribe Autolytus : the one, A. cornutus, a small form 

 first described by A. Agassiz (10), which occurs in abundance 

 on the stems of Eudendrion and Penaria in the early part of 

 the summer, before the appearance of A. varians ; the other, 

 Procerea ornatus (Verrill), very much larger, and appearing in 

 numbers among the stems of Eudendrion and Parypha later 

 in the summer, after A. varians has become less abundant. In 

 both of these species the phenomena of stolonization are essen- 

 tially different from that of A. varians. Individual specimens 

 of these three species may be found at any season of the year 

 in process of budding. 



Methods. — For surface study living specimens were used 

 almost exclusively, the distortions produced by the killing fluids 

 frequently being so marked as to make some of the most impor- 

 tant details uncertain. By allowing the animals to remain in 

 a small quantity of sea water until it becomes somewhat stag- 

 nant, they become sufficiently inactive to permit the employment 

 of pressure and considerable manipulation without producing 



