MUSEUM OF COMPARATIVE ZOOLOGY, 243 



Lafoea robusta sp. nov. 



Plate IT. Fig. 24. 



Trophosome. — Hydrothecso large, tubular; tapering at the base, expanding 

 slightly at the terminal orifice, borne on short, stout peduncles which arise at 

 short intervals from the creeping hydrorhiza. 



Gonosome. — Unknown. 



Locality. — Long. 84° 21' W. Depth, 101 fathoms. 



This is a stout creeping form. The hydrothecEB are similar to those of 

 L. fruticosa except in the characters of the peduncle. Occasionally there is an 

 attempt at annulation seen in the peduncle, and there is considerable variation 

 in the form of the hydrothecae. 



Lafoea eonvallaria Allman. 



Plate IT. Fig. 83. 



One of the half-dozen fine specimens of this form in the collection bears a 

 mimber of gonangia. The colony on which they occur is about two inches in 

 height, and the gonangia are attached in a dense cluster to the main stem and 

 to the bases of two or three of the branches ; they are sessile and anchor-shaped, 

 with the orifices, of which there are two in each gonangium, at the extremities 

 of the obtusely pointed flukes. 



Localities. — Off Havana, Cuba, 160-177 fathoms. Lat. 25° 33' N., Long. 

 84° 21' W. Depth, 101 fathoms. 



This style of gonangium is of unusual interest, as it is, I believe, the only 

 one known with two external orifices, and any addition to our knowledge of 

 the gonosomes of the Lafoeidce is so seldom obtained that any new facts in this 

 direction are very acceptable. It is somewhat remarkable that so little should 

 be known in regard to the reproductive processes, and the structures in which 

 they are developed, of a family in which there are such long-known and wide- 

 spread species as occur in the Lafoeidce. I have examined large quantities of 

 L. dumosa from different parts of the world, taken at different depths, from 

 waters of different temperatures, and at different seasons of the year, and yet, 

 with all the examinations which have been made by various zoologists, I 

 believe we know nothing as yet of the gonosome. And the same is true of 

 all other species of the genus, I think, with the exceptions of L. calcarata 

 A. Agassiz, and L. eonvallaria AlLnan. These two forms are so different in style 

 as to make it seem probable that when our knowledge of their life-histories 

 becomes complete it may be necessary to separate them generically. 



Lafoea vennsta Allman. 



A few of the graceful hydrotheca) of this species were found creeping over 

 the stem of Obelia marginata, collected ten miles north of Zoblos Island. 



Lafoea gracillima Aldeb. 



A number of fine specimens of this delicate form were taken in Lat. 25° 33' 

 N., and Long. 84° 21' W., at a depth of 101 fathoms. No gonangia present. 



