186 PROCEEDINGS OF THE AMERICAN ACADEMY 



the members of the whorl have reached the substratum and have 

 become attached. This generally occurs at a place where two of 

 the hapteres of the first set remain close together. In such a case 

 the secondary hapteres may never develop at all, and their place 

 may be permanently supplied by members of the first whorl. But, as 

 a general rule, all the hapteres of this second set reach their full 

 development, and constitute the important part of the permanent hold- 

 fast. The smallest specimen examined which shows the protuberances 

 that are to grow out into the secondary hapteres is 16 cm. long, while 

 one that has reached a leugth of 30.5 cm. has most of the second set 

 attached, but many of them only slightly. In this specimen the primi- 

 tive disk has entirely disappeared, and there are five hapteres of the 

 first set, which is apparently the original number. Of the second set 

 only two are firmly attached ; three are just touching the substratum ; 

 and there are two more just showing as small protuberances from 

 the disk of the rhizogen. The stipe of this specimen is 5 cm. long 

 and 3 mm. in diameter at the base. Below, it is cylindrical, but in 

 the upper portion it is noticeably flattened. Even in a specimen of 

 this size the stipe expands gradually into the blade, which in what 

 seems to be the most common form in New England is broader in pro- 

 portion to the length than in previous stages. This blade is elliptical- 

 lanceolate, 25.5 cm. long and 4.8 cm. wide in the broadest part, which 

 is about half the length from the base. Tlie cryptostomata are very 

 abundant and very conspicuous. 



All of the previously mentioned forms were obtained from the pools 

 at Nahant in the gatherings made on April 24 and 25, 1889. The two 

 or three largest and most developed specimens came from below low- 

 water mark, while the younger specimens came for the most part from 

 the uppermost pools. On May 12, some specimens collected from the 

 higher pools were about as large as the largest specimens of the first 

 collection. 



On May 25, a few specimens were collected at Peak's Island, 

 Maine, the measurements of some of which are given in the following 

 table : — 



