run: 



CHISMOBUANCHIATA. 



and devoured by birds and fihe; Init during the summer of 1836 

 we discovered tW it bad a very fonuidable enemy in an insect of iu 

 own order. A fly, which dourly ranmbled the hunae-fly, wu 

 observed in groat abundance on the mud which had just been left by 

 the retiring water, and we found them assembled in little group* of 

 fire or six, in the act of extracting the blood-worms from their holes, 

 using the proboacia for this purpoee : hut no sooner was the worm 

 fairly duiodged than a battle ensued, for each apparently wished to 

 hare the worm to iteelf ; tboee that kept ponoeiion sucked out the 

 fluids from the worm. 



The pupa is of a brownuh colour ; the body is cylindrical, the 

 head, thorax, wings, and leg* are inclosed in separate sheaths, and, 

 with the exception of the two fore legs, lie in a clone and compact 

 man ; the fore leg*, covered by their sheath*, project from each sidu 

 of the thorax. In this as well aa in the larva state, the animal live* 

 in the water. The breathing apparatus consists of two appendages, 

 one on each side of the thorax, and each is composed of five branchen 

 which spring from a common centre. 



When the insect is ready to quit its pupa case, it gains the surface 

 of the water, and there remains suspended for some little time with 

 the disc of the thorax slightly protruded ; this part burnt* down the 

 middle, and the insect, which is hairy, and hence does not easily wet, 

 places its feet upon the surface of the water, where it floats (if the 

 weather be calm) with the greatest safety. We observed, upon taking 

 one upon our finger, that the wings are at first opaque and white, 

 and filled with a fluid ; but in a minute this fluid was expelled, and 

 the sides of the wings collapsed and became transparent. The fluid 

 thus ejected we perceived on' our finger beneath the insect, but 

 could not ascertain from what part of the wing or body it made its 

 -.;.. 



Discussions have arisen on the means which this animal possesses 

 of suspending iteelf at the surface of the water without motion, it - 

 specific gravity being supposed to be greater than water. 



Messrs. Kirby and Spence account for it by a kind of propelling 

 power which the centre of the thorax possesses, and state that this 

 part being thus protruded and drying, the attraction of the air to the 

 dry portion of the thorax is sufficient to overcome the slight difference 

 in the specific gravity between the animal and the element ; but it is 

 further stated that if a drop of water fall upon the insect at thi 

 time it will immediately sink. 



We have kept these insects in a glass jar for the purpose of 

 observing their habits, and are very much inclined to doubt that the 

 specific gravity of the pupa is greater than that of the water, at the 

 time just previous to the transformation from pupa to the imago 

 state. Indeed at this time it appeared that they could not keep 

 from the surface, unless they were in motion. Whenever we 

 approached the jar, being at the top, they immediately descended 

 by a quick zigzag movement of the body ; but upon our remaining 

 quiet for a moment they ceased all motion and rose to the surface 

 again. We imagine that at this time the animal within iiaving 

 become partially disengaged from the pupa case, the space between 

 the two is filled with air, that this would be sufficient to overcome 

 the difference of specific gravity between the animal and the water, 

 and that there would most probably be more air in the region of the 

 thorax than elsewhere ; and hence this part U protruded front the 

 water. 



The perfect insect is of a pale-ash colour, and is a little larger than 

 the common gnat, which it resembles. This, as well as others of the 

 genus, is remarkable for its habit of carrying the two fore legs in a 

 horizontal position ; they project in front, and might be mistaken for 

 antenna; ; these Utter organs however are very beautiful, and in the 

 males resemble little plumes. 



C'HI'ROTES, a genus of Saurians separated by Cuvier, and, accord- 

 ing to him, resembling the C'haJcuIti in their verticillated scales, and 

 the Ampkiibftna still more in the obtuse form of their head ; but 

 distinguished from the first by their want of posterior feet, and from 

 the last by their possession of anterior limbs. The same author adds, 

 in a note to the last edition of the ' Kegne Animal,' that the genera 

 which terminate this order of Saurians are interposed in various 

 manners between the ordinary Saurians and the genera which aro 

 placed at the bead of the ordi-r Ophidians to ouch a point, that many 

 naturalists are now of opinion that the two orders ought no longer to 

 be separated, or rather that one order should be established, com- 

 prising on the one part the Saurians, with the exception of the 

 CrocwiUiJcr, and on the other the Ophidians of the family Anyuidir. 

 Hut he observes that there exist, among the Tonsil forms of the ancient 

 calcareous beds, two very extraordinary genera (/chihyniattriu and 

 PUtiotaunu), which, with the bead and trunk of a Saurian, have feet 

 attached to abort limbs, and formed of a multitude of small articula- 

 tions conjoined so as to form a kind of paddle or fin, like the anterior 

 paddles or fin-feet of whales. These ought, he adds, to form a very 

 distinct family. In their osteology they approach the Saurians, 

 properly so called, much Dearer than the Crocodiles, with which 

 Kit/.inger associates them in his family jMrirnla ; though in the fossils 

 there is no trace either of scales or of the tongue, the two parts on 

 which the characters of the Loricala rat. 



These Bimanous Reptiles, as Cuvier terms them, include, according 

 to him, but one species, which is a native of Mexico. This U the 



Bimane CannaU (Ckiroia tonal ie^altu) of riui.-r. Bipode Canneltfof 

 Laoepede, OMMMMNV JNVfNM ,.f Sclm.-ider, and IsurrtalHmbrirvtd* 

 of Shaw. The animal has two short feet with four toe* on each (and 

 the vestige of a fifth) sufficiently organised internally, and attached 

 by means of scapula?, clavicles, and a small sternum ; but the head, 

 the vertebras, and, in short, all the rest of the skeleton resemble that 

 of the Am/ihiMlHrntr. Dr. J. K. Gray refer* Ckirolet to a third family 

 of the Auiphisbmian* which he calls CUrotida. 



Cliirotri canaJirulalut (C. lumbricmda, Fleming; C. Mexican**, 

 Bory ; Bipa canalirnlatia, Bonnaterre ; dtamirtaunuprupui, Sclmit / ; 

 Ckalfidet prop**, Daudin), is about the size of a human littl. 

 and is from right to t. n inches long. It in of a flerh < 

 and covrrrd with about 'J'Jo il, -mi-rings on the back, and as many 

 under the belly, which meet, in alternating, on the side. The tongue i* 

 but little extensile, and is terminated by two (mall horny points. The 

 eye is very minute. The tympanum is covered with skin and 

 invisible externally. Above the vent are two lines of pores. It is a 

 native of South America, 



Chirotrt cannlifulatuf, 



CHI'UUS, a genus of Fishes belonging to the section A eanlhopttryyii 

 and the family 6vbiod<r. The species of this genus have the body con- 

 si.lrrubly elongated, furnished with ciliated scales, and the mouth not 

 deeply cleft ; the teeth are small and conical ; but the most remarkable 

 character consists in the body being furnished with several longitu- 

 dinal lines of pores, similar to the ordinary lateral line. Some of tin- 

 species have appendages over the eyes, as observed in the Blennies ; 

 their ventral fins have each five soft rays : the spines of the dorsal fin 

 are slender, and this fin extends nearly iln- whole length of the back. 



Cuvier says that it is with hesitation that he places this genus with 

 the family above mentioned, and that it will probably one day form 

 the type of a separate family. All the species as yet discovered 

 inhabit the seas of Kamtchatka they are included in the gi mm 

 Lasbrajf by Pallas, who describes several of the species in the ' Memoirs 

 of the Academy of St. Petenburgh,' vol. ii. 



CHISMOBKANCHIATA, an order of Molhuca, forming, in 

 De Blainville's system, the second order of his second sub-class, 

 Paratephalaphora Monoica. The following is his definition of tin- 

 order : Organ* of respiration aquatic, branchial or pectinated, 

 situated at the anterior part of the back, in a large cavity communi- 

 cating with the ambient fluid by a wide oblique anterior slit. Mouth 

 toothless, but provided with a long lingual riband-like organ. Sin 11 

 either none, or internal, or external, very much depressed, with a 

 very large entire aperture, and without any pillar (columella). 



This definition is incorrect, in so far as it states that in some 

 instances there is no shell; for CoriaceUa, the only genus dewnh.,1 

 by De Blainville as being without any shell, has a horny one, ns 

 Cuvier observes, though it U very delicate and flexible and nearly 

 membranous. Cuvier, who places three of the genera, >Vy 

 VoriuctUa, and Cryptotlom/i, under his Capuluida, a family 

 order tiatltropoda ptctmiltranchiata, observes that De Blainvilli- 

 places the greater part of the Capuloida under hi* non-symmetrical 



