MOLLUSCA. 71 



297. Pythin a Deshayesiana, (Plate XIX. fig. 8, 9.) Testa transversa, subtrigona, polita, alba, 

 sulcis tribus medio divaricatis ornata, intevstitiis rotundatis ; margine rectiuscula. 



Inhab. New Ireland. 



The present interesting and remarkable shell seems to have been brought to 

 England many years back, as Mr. G. B. Sowerby, drawing on his unrivalled fund 

 of information in Conchology, informs me that it was known in the collection of 

 Mr. Humphreys. It has recently, together with another undescribed species, 

 been collected in the Philippine Islands by Mr. Cuming. The same generic form 

 is also known in a fossil state, as a shell is represented by Deshayes, Coq. Foss. 

 des env. de Paris, v. i. t. xl. f. 4, 5, 6, under the name of Modiola arcuata, 

 Lamarck, which unquestionably belongs here. Like the undescribed species in 

 Mr. Cuming's collection, this fossil shell is remarkably constricted towards the 

 middle of its interior margin, causing the lateral portions to appear as two lobes. 

 Mr. Sowerby also informs me that he has seen another and somewhat orbicular 

 species, which should be referred to this group. 



Family — LiNGULACEiE. 



Lingula. Bruguihres. 



298. Lingula albida, (Plate XIX. fig. 4.) Testa, oblonga, lasvi, complanata, antice truncata, 

 ubique albida ; pediculo brevi, cylindraceo. 



Inhab. Bay of Magdalena, California. In seven fathoms, among sandy mud. 

 This species is distinguished by its uniform dead white colour and very short 

 pedicle, which does not exceed half the length of the shelly portion. 



CIRRIPEDA. 



Family — AnatifacejE. 



Tkilasmis.* Hinds. 



Testa pedunculata, trivalvis. Valvse duse laterales suboblique ovales, complanatre, laevigata?, 

 albae; tertia dorsalis linearis, carinata. Pedunculus brevis, lsevis. 



* Trilasmis ; the Greek numeral for three, and eXaafia, a plate. 



