THE NAUTILUS. Ill 



from the unbones, in front of which the valves are more or less con- 

 stricted, and, on the base, flattened, giving a slightly arcuate aspect 

 to the shell; valves with a very slight ratiier anterior gape; interior 

 polished, dark blue, much as in Mytilus edu/is, the ligament long, 

 the anterior margin with three or four crenulations corresponding to 

 the external radial grooves. Length 19; max. heiglit G.5; diameter 

 5.5; unbones behind the anterior end of shell 1.0 mm. 



This shell recalls Adula of Carpenter but seems not to be a borer, 

 and is without the peculiar fine transverse sculpture of the two 

 Californian species of Adula. It may possibly be referable to the 

 genns Myrina. 



In Miss Cooke's collection, which is notable for tlie Gulf of 

 California shells collected by the late Capt. Porter, one of the things 

 most striking to the visitor is her fine series of polished specimens 

 of the rare red variety of Haliotis crucherodii. Her best specimen, 

 of a glowing vermilion, is resplendant. Among the specimens 

 interesting as extending the known range, in her collection, are 

 Mitra belcheri Swainson, from Magdalena Bay, Lower California; 

 Cymatium wiegmanni, from the same locality; Stromhiis peniiu'anus 

 from tiie Tres Marias Islands, and Pachyponia inaquale without 

 waves and with a finer type of sculpture, from San Diego. A form 

 of Pachypoma, which appears to be new, is from the Gulf of Cali- 

 fornia. It is somewhat smaller than the average inaqunle., has much 

 the same color and sculpture, but is proportionately much higher and 

 narrower, having much the form of ' Chlorostoma ' brunneum. It 

 might be called for the present P. incequale var. spiratum. 



One of the most interesting and surprising facts is conclusively 

 proven by material in this collection. Specimens of the " Uvanilla" 

 regina, Stearns, with the dried animal having the operculum still 

 attached to it, show that the species is a Tegvla,* notwithstanding 

 the remarkable resemblance of the shell to the true Uvanillas of 

 the Gulf, which possess a heavy calcareous operculum. In the 

 regina the operculum is horny and moderately multispiral. This 

 fact had indeed been previously mentioned to me, but it was not 

 until I saw the operculum actually attached to the animal, that I was 

 relieved of a lingering doubt as to whether some mistake had not 

 been made. 



* More commonlj' called by the name Chlorostoma. 



