196 BULLETIN OF THE BUREAU OF FISHERIES. 



are rather wide, and the valve margins usually not very distinct. The color is dirty gray, with most 

 of the valves more or less purplish or livid. The scutum has subparallel occludent and lateral margins 

 and very oblique tergal margin. The basal margin runs at a right angle from the occludent. 



The tergum is very long and narrow, its occludent and carinal margins slightly convex, the lower 

 margin sinuous. 



The carina is simply arched with apical umbo and convex roof. The upper half of the valve has 

 the roof defined by small lateral ridges, but these become weaker anil finally obsolete below, where the 

 valve is wider and the convex roof passes into the sides without distinct boundary. The sides are 

 narrow throughout and excavated in a shallow furrow along the lateral ridges. The carina extends 

 upward to the middle of the carinal margin of the tergum. 



The upper lateral plate is trapezoidal, the carinal, tergal, and scutal margins slightly convex, the 

 basal margin straight and abutting on the inframedian lateral plate only. The angles are somewhat 

 rounded off, and the umbo is at the tergo-scutal angle. 



The rostrum is small, subtriangular, with apical umbo. The rostro-lateral plate is small and 

 wedge-shaped, being narrower in front. 



The inframedian lateral plate is well developed, nearly square, as wide as high, its forward (or 

 ventral) margin convex, and bounded more by tin- scutum than by the rostro-lateral plate. The other 

 margins are straight. The umbo is central. 



The carino-lateral plate is small, irregularly reniform or lunate with blunt ends, with concave 

 carinal margin and convex latero-basal margin. The umbones scarcely project at the base of the 

 carina. 



The peduncle is long, approaching the capitulum in length, its lower half cylindric, upper half 

 gradually widening to the width of the base of the capitulum. It is very closely and regularly clothed 

 with rather small lozenge-shaped scales, of which there are 20 or more in a longitudinal row. 



Length of capitulum 15 mm., width 7 mm., diameter 1 mm. Length of carina 11 mm. Length 

 of peduncle 11.5 mm., diameter in the middle 3 mm. 



The rami of the first pair of cirri are very short, with globose segments, 11 and 12 in number. The 

 other cirri are long, composed of long segments, which bear from 5 on the second cirri to 6 pairs of 

 spines on the fifth and sixth cirri. 



Albatross stations 4558, 4555, 4551, 4452, 4535, 4439, off Point Pinos light-House in 40 to 86 fathoms, 

 on mud and rock bottom; the types, no. 32411 U. S. National Museum, from station 4558. Topotypes 

 no. 32412. Seated on annelid tubes, etc. Apparently abundant in the region of Monterey Bay. 



S. ealifornieum is an abundant form in comparatively shallow water. It is related to S. groen- 

 landicum and S. angustum, of the extreme northern Atlantic, but in these the general shape of the 

 capitulum differs, and most of the plates show more or less diversity. The rostro-lateral plate is much 

 higher in both of the Atlantic forms. 



Most of the specimens are smaller than the type, the capitulum 10 to 12 mm. long, with the peduncle 

 less closely scaly. The livid or dried-blood color of the valves or parts of them is variable, some indi- 

 viduals being white. The peduncle varies a great deal in length. It is sometimes only half the length 

 of the capitulum, and yet not more closely scaly than in other individuals with long peduncles. 



The figures are from washed specimens with the enveloping membrane partly removed in order to 

 show the valves clearly. Their outlines are much less distinct in uncleaned individuals. 



Scalpellum ealifornieum osseum n. subsp. 



[PI. v., fig. 7.] 



Similar in general characters to S. ealifornieum, but the valves are more completely calcified, while, 

 with distinct outlines and clear-CUl angles, though covered with a thin, transparent, densely pilose 

 membrane. Upper lateral plate distinctly pentagonal, the scutal and tergal margins longest. Tergum 

 shorter and wider than in californiewm. Peduncle long, very sparsely scaly, the scales white; pilose. 

 Length of capitulum, 0.5 mm. 



Type, ho. 32413 If. S. National Museum, from Albatross Btation 4454, off Point Pinos Light-House. 7 1 

 fathoms. Taken also at station 447s. Santa Cruz Light-House. 30 fathoms. 



The large number of individuals of «S. ealifornieum . at all stages of growth, which I have examined 

 -bow ilia t i he above-described form is not a young stage of thai species, although it is similar in the num- 

 ber and proporl ions of the valves. 



