October 1, 1890.] 



K N O WL EDGE 



225 



vast, and muros, a lizard. For a long period little or 

 nothing more was known of the structure of this huge 

 creature, but at length specimens were olitained from the 

 Wealdeu of the Isle of Wight which indicated the nature 

 of its teeth and various parts of its skeleton ; while valu- 

 able information was also afforded by specimens obtained 

 from the Kimeridge and Oxford clays, which underlie the 

 Wealden beds. It is true, indeed, that the specimens from 

 the Isle of Wight have been described under a different 

 name from those fi'om Sussex, but tliey differ only in 

 minute points of detail. The tooth shown in woodcut 3 

 is that of the Isle of Wight reptile, to which the name of 

 Hoplosaur (armed lizard) has been applied. It will be 

 seen that this type of tooth is quite different from that of 

 the Iguanodon, the outer surface of the crown being convex, 

 without flutiugs, and with smooth edges ; while the inner 

 surface is concave, and .spoon-like. Specimens of similar 

 teeth from the Sussex Wealden, which evidently belong to 

 the Pelorosaur, are much larger than 

 the figured tooth. The structure of 

 the haunch-bones of these creatures is 

 quite different from that of the Iguano- 

 don, and more like that of the croco- 

 diles, so that it is perfectly evident 

 that they exhibited no especial bird- 

 like affinities. These reptiles may, 

 indeed, be more correctly compared 

 with crocodiles, which they resembled 

 in walking on all four feet ; although 

 in many points of their organization 

 they were allied to the Iguanodon, and 

 thus indicate how the latter has pro- 

 bably been derived from reptiles more 

 closely resembling crocodiles. 



The teeth of the Hoplosaur, al- 

 though so unlike those of the Iguano- 

 don, likewise indicate that their owners 

 w ere of herbivorous habits. The gigan- 

 tic bulk of these creatures is indicated 

 not only by the arm-bone mentioned 

 iiliove, but also by another arm-bone 

 obtained from the Kimeridge clay, 

 which measures 57 inches in length, 

 as well as by the thigh-bone of the 

 allied Cetiosaur (whale-lizard) from 

 the still older Stone.sfield slate of 

 Oxfordshire, which is upwards of 64 

 inches in length. The latter dimen- 

 sions — stupendous as they are — are, however, exceeded 

 l)y another thigh-bone from the United States, which 

 actually measures upwards of 71 inches, or G feet 2 

 inches. The owner of this enormous bone has been appro- 

 priately named the Atlantosaur, and appears to have been 

 the largest land animal yet known, alongside of which a full- 

 grown elephant would be a mere pigmy. The total length 

 of another nearly related but smaller American species 

 is, indeed, estimated to have been as much as 80 feet. 



Another peculiarity of these reptiles, which must not 

 be passed over, occurs in the joints of the backbone, or 

 vertebra'. In creatures of such enormous bulk, if the 

 vertebnc were solid their weight would probably be an 

 impediment to the free movements of the body ; and we 

 accordingly find that these vc^rtebne were excavated into 

 hollow chambers. A similar i'eature is kiuwn elsewhere 

 only ill birds, where these diaiubers are filled with air. 

 We must not, however, omit to mention that similar 

 chambers dcciir in the vertebia' of the smaller members 

 of the group uiiilcr consideration. 



{I'd !„■ cmtiniMl.) 



Fh ? — Oi rm SiK 



[ALk Ot Till TOOIH 



OF THE Hoplosaur. 

 Nat. size. 



THE BED-BUG.-II. 



By E. a. Butler. 



A FEW words are necessary to complete our picture of 

 the bed-bug's head, for we have yet to speak of 

 the antennse and eyes. The former (Fig. 5) pro- 

 ceed from the upper surface of that part of the 

 head which lies between the eyes and the base of 

 the rostrum, and are remarkable for the small number of 

 their joints, four only being discernible ; the basal joint is 

 small and stout, but the other three long, and, except the 

 second, very slender, much finer, in fact, than a human 

 hair. In the fewness and length of the joints of the 

 antenna', the bed-bug is quite in accord with the rest of 

 the members of the division of Hemiptera to wliich it 

 belongs, \'iz. the Heteroptera. One usually thinks of 

 antennse as composed of a great number of short joints, 

 and such an idea would be correct for the vast majority of 

 insects, but not for the Heteroptera, in which sub-order 

 alone we find antenme composed of a small number of 

 long joints. Like all the rest of the body, the bug's 

 antemiiB are clothed with hairs, which are, no doubt, 

 more or less sensory in function ; those on the basal joints 

 are mttch coarser and more thickly set than those towards 

 the tip. The last joint, as will be observed from the 

 figure, is slightly clubbed at the end, and is probably the 

 most highly sensitive part. 



The eyes are black and very prominent, appearing as 

 two masses like little blackberries at the sides of the head, 

 reminding one of the corresponding organs in certain 

 small ant-like beetles {I'sclnphidd) which inhabit moss, or 

 lurk under stones. The bed-bug is somewhat exceptional 

 amongst Hemiptera in not possessing, in addition to its 

 compound eyes, the small simple ones called " oceUi." 



Fig. 5. — Antenna of Bkd-Bug. Fig. G. — Prothora.x ok Bei>-Bi,g. 

 A, head ; .•.-, scutellum. 



Two such are usually to be found, in this order, between 

 the compound eyes, but our present insect is destitute of 

 them. 



The thorax, or, as we ought rather to say, the prothorax 

 (Fig. (5) is curiously shaped, being much wider than long, 

 and having broad leaf-like expansions of its chitinous 

 covering at its sides ; these run forward by the side of the 

 head almost as far as the eyes, and so form a notch into 

 which the head loosely fits, and whereby its sideward 

 motion is considerably restricted, as if by a stiff collar. 

 A similar peculiarity, viz. the winged margin to the 

 thorax, will be familiar to microscopists as occurring in 

 the little lattice-winged insects called "thistle-bugs" 

 {^[ollantln(l ninhii), which are found abundantly on thistle- 

 heads, and are often mounted whole as opaque objects for 

 the microscope, under the name of Tiiuiis. The other 

 two segments which go to make up the complete thorax 

 are not very easy to trace above, though evident enough 

 beneath. The only part that appears prominently is a 

 central triangular plate of the mesothorax, called the 

 scKlillioii. On each side of this we see the fore-wings, 

 which are in a very rudimentary condition, and, for- 

 tunately for our comfort and peace of mind, quite useless 

 for (light. 



In these little scale-like appendages can still be recog- 



