127 



brought with the living ones. T have hitherto found them only in one lot of 

 thirty or forty loads of shells, of which I kin the exact source. 



They are by no means scarce, and several hundred specimens must have been 

 obtained by myself and others." 



From the condition of the dried animal matter contained in Mime of the spe- 

 cimens, I quite agree with Mr. Smith's conjecture that the species is probably 

 still living at the locality mentioned. In many cases where this species has 

 bored from the outside of the oyster shell, penetrating entirely through its or- 

 dinary surface, the oyster has protected itself from contact by depositing a 

 layer of nacre betweeu itself and the exposed portion of the intruder. 



Dactylina (Gitocentedm) Chiloensis, King. 



To the synonymy of this species must be added Pholas (_Dactyuxa) retifer. 

 Morch. Mai*. Bliitt. vii. p. 177, Dec. 1860. 



Description. — T. elongato-cylindracea fere clausa, antice rotundato subpro- 

 ducta, postice elongata planata laeviuscula; costae 25 par urn prominentes lon- 

 gitudinalibus validioribus decussate, intersectionibus squamiferis ; costae sub- 

 aequales, quarta antica parvula ; interstitia costarum lirulis planis 4-5 ; costae 

 anticae et lirulae intermediae validiore.-, fascie interna excavate ; lamina dor- 

 salis reflexa unde late umbilicata; cellula? dorsales ad num. 12 inaequales. 



Long 104, alt. 33 mill. Realejo, valva solitaria dextra fractra." 



The intermediate flat ribs or lirute mentioned above and considered by 

 Morch to be a distinctive character, are very apparent at the anterior end of 

 most perfect and fresh valves of C h i 1 o e n s i s, and they are frequently marked 

 internally by corresponding sulcae; as the shell grows to maturity these riblets 

 become obsolete, or are replaced by a single intermediate squamiferus small 

 rib. 



There is no regularity in the number of radiating costae on the surface, though 

 they do generally average twenty-five in number; but in some valves they be- 

 come evanescent posteriorly sooner than in others. The dorsal cellules num- 

 ber in different specimens before me from 12 to 15. 



It will be seen that Morch describes his species from a single valve, and in 

 the course of his remarks upon its distinctive characters, he refers to the 

 figures of Chiloensis in Philippi Abbild. The examination of a few spe- 

 cimens would have satisfied him of the entire identity of his shell with 

 Chiloensis. 



