LEPAS FASCICULARIS. 93 



Indian Archipelago, off Borneo and Celebes ; Pacific Ocean, between the 

 Sandwich and Mariana Archipelagos ; New Zealand : attached to fuci, Spirulse 

 Janthinse, YeleDas, often to feathers and cork ; often associated with the 

 young of L. anserifera, (var. dilatata^) and L. pectinata. 



General Appearance. — Capitulum highly variable in 

 all its characters ; thick and broad in proportion to its 

 length, but the breadth is variable, — in some specimens, 

 the capitulum being longer by one-fifth of its total length 

 than broad ; in others, one-fifth broader than long. Valves 

 generally approximate ; in some varieties, however, from 

 the narrowness of the carina and terga, the valves stand 

 far apart, there being an interval between the carina 

 and scuta of nearly half the breadth of the latter. Valves 

 excessively thin, brittle, transparent, colourless, smooth, 

 but generally sinuous along the zones of growth, which are 

 conspicuous : valves generally covered throughout by thin 

 chitine membrane, which is thickly clothed, especially in 

 the interspaces between the valves, with minute spines, 

 barely visible to the naked eye. Scuta with the lower 

 part of the tergo-carinal margin extremely protuberant ; 

 occludent margin, more or less, but slightly reflexed, 

 with a depressed line running from the umbo to the 

 apex; basal margin much reflexed, but to a variable 

 extent and at a varying angle, even up to a right angle, 

 — an external rim or collar being thus formed. There 

 are no distinct internal teeth, but the basal margin 

 under the umbones, is more or less distinctly produced 

 into a rounded disc or projection, which is generally 

 not so much outwardly reflexed as the rest of the basal 

 margin : there is no distinct internal basal rim. The 

 primordial valves are generally visible, but they do not 

 lie, as in all other species, close to the basal margin, but 

 a little above it, — the lower reflexed portion having been 

 subsequently developed. Terga flat, with the occludent 

 margin slightly arched, and not, as in the foregoing spe- 

 cies, formed of two sides ; apex bent towards the carina ; 

 width of the lower half highly variable, owing to the 

 varying extent to which the scutal margin is hollowed 



