30 Mr. Walker's descriptions of Chalcidites/rom Conception. 



I have taken as many as thirty-four perfect shells from one 

 cup, showing that they are prolific. 



They fix these cups in indentations and crevices and under 

 overhanging parts of the rocks, and invariably on that side 

 least exposed to the fury of the waves ; and this circumstance 

 shows that even in this animal the Great Author of all has im- 

 planted a sense of guarding its young from injury, proving 

 his superintending care over all his creatures. 



The accompanying drawings will illustrate the above state- 

 ment : — 



Plate I. A, 



Fig. 1. Nidi taken from under the whelk when in the act of forming it. 



— 2. Nidi after the escape of the young. 



— 3. Magnified view of the upper part or operculum when left by the 



whelk. 



IX. — Descriptions of Chalcidites discovered near Conception, 

 in South America, by C. Darwin, Esq. By Francis 

 Walker, F.L.S. 



Lamprotatus Alcander, Mas. JEneo-viridis capreo et cyaneo varius, an- 

 tenna fulvce, pedes fulvi, ales limpidce. 



Corpus breve, robustum, convexum, aeneo-viride, nitens, scitissime squa- 

 meum, parce hirtum : caput transversum, breve, viride, thorace paullo latius ; 

 vertex latus, frons impressa, abrupte declivis : oculi run, mediocres, non ex- 

 tantes: antennae fulvae, subfiliformes, thorace non longiores ; articulus l us 

 nigro-viridis, longus, gracilis ; 2 US longicyathiformis ; 3 US et 4 US brevissimi ; 

 5 US etsequentes usque ad 10 um breves, approximati, subaequales; clavalon- 

 giconica, compressa, acuminata, articulo 10° duplo longior : thorax ovatus, 

 cupreo-aeneus : prothorax brevissimus : mesothoracis scutum cyaneo-viride, 

 longitudine latius ; parapsidum suturae bene determinatae, postice approxi- 

 mates ; scutellum subrotundum : paraptera et epimera magna : metathorax 

 mediocris, obconicus, declivis : petiolus sat longus : abdomen breviovatum, 

 cupreo-varium, supra planum, basi cyaneo-viride, thorace multo brevius ; 

 segmentum ] um magnum, 2 um et sequentia brevia : pedes fulvi, simplices, 

 subaequales ; coxae virides ; tarsi apice fusci : alse amplae, limpidae ; squamulae 

 fuscae ; nervi fulvi ; nervus humeralis ulnari fere duplo longior, radialis 

 ulnari non brevior, cubitali multo longior ; stigma minutum. (Corp. long, 

 lin. 1 ; alar. lin. 2.) 



Gastrancistrus Cephalon, Fern. Cupreus, antennce nigra, pedes lutei, 

 femora basi nigra, alee limpidce. 



Corpus cupreum, convexum, nitens, scitissime squameum, parce hirtum ; 

 caput transversum, breve, thorace latius; vertex latus; frons impressa, 

 abrupte declivis : oculi run, mediocres, non extantes : antennas subclavatae, 

 nigrae, satgraciles, submoniliformes, thorace non longiores; articulus l us lon- 

 gus, sublinearis ; 2 US cyathiformis ; 3 US et 4 US minimi ; 5 US et sequentes usque 

 ad 10 um breves, approximati, subaequales; clava longiconica, acuminata, ar- 

 ticulo 10° plus duplo longior: thorax ovatus: prothorax transversus, me- 

 diocris, antice angustus : mesothoracis scutum longitudine latius ; parapsi- 

 dum suturae bene determinatae, postice approximatae ; scutellum subconicum: 

 metathorax brevis, postice angustus : petiolus brevissimus : abdomen ova- 



