19() BULLETIN OF THE BUREAU OF FISHERIES. 



arc i-iitlu'i- wide, and the \al\c' margins usually not very distinct. Tlu' color is dirty gray, with most 

 of the valves more or less jjurplish or livid. The sciitimi has subparallel occliident and lateral margins 

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



The tergimi is very long and narrow, its ocelndent and earinal margins .slightly convex, the lower 

 margin sinuous. 



The carina is simply arche<l with apiial umbo and convex roof. The upper half of the valve has 

 the roof defined by small lateral ridges, Imt these become weaker and finally obsolete below, where the 

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

 narrow throughout an<l excavated in a shallow furrow along the lateral ridges. The carina extends 

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



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

 basal margin straight and al>utting on the inframedian lateral i>lat(» only. The angles are somewhat 

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



The rostrum is small, subtrianguUir. with apical uml)o. The rostro-lateral plate is small and 

 wedge-.shaped , being narrower in front. 



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

 ventral I margin convex, and bounded more by- the scutimi than by the rostro-lateral plate. The other 

 margins are straight. The umbo is central. 



The cari no-lateral plate is small, irregiilarh' reniforin or lunate with Viliint ends, with concave 

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

 carina. 



The peduncle is long, approaching tiie <-apitulum in length, its lower half cylindric. upper half 

 gradually widening to the width of the base of the t'apitulum. It is very closely and ri-gularly 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 4 mm. Length of carina 11 mm. Length 

 of peduncle 11. .5 mm., diameter in the middle X mm. 



The rami of the first jiair of cirri are very short, witli gloliose segments, 11 and 12 in nimiber. The 

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

 spines on the fifth and sixth cirri. 



Alhatross stations 4558, 4555, 4551, 4452, 4535, 4439, off Point Pinos Light-House in 40 to 8G fathoms, 

 on mud and rock bottom; the types, bo. 32411 U. S. National Mu.seum, from station 4558, Topotypes 

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



S. culifoniicuiii is an abimdant form in comparatively shallow water. It is related to S. qrcen- 

 laiwUcnm and S. angiistnm. of the extreme northern Atlantic, but in these the general shape of the 

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

 higher in both of the .\llantic 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 clearh'. Their outlines are much less distinct in uncleaned individuals. 



Scalpellum californicum osseum n. sul)sp. 



|P1. VI, lig. 7.] 



Similar in general characters to S. californinim. but the valves are more completely calcified, white, 

 with distinct outlines and clear-cut angles, though covered with a thin, transparent, densely i)ilose 

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

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

 Length of capitulum, (i,5 mm. 



Type, no. 32413 U. S. National Museum, from Albatross station 4454, off Point Pinos Light-House, 71 

 fathoms. Taken also at station 4478, Santa Cruz Light-House, 30 fathoms. 



The large number of individuals of .9. californicum, at all stages of growth, which I have examined 

 show that the above-deseriljed form is not a young .stage of that species, althovigh it is similar in the num- 

 l«T ;inil jiroporlions of the valves. 



