MEMOIRS OP THE NATIONAL ACADEMY OP SCIENCES. 115 



In Fig. G the microtome knife passed through the front region of the right olfactory lobe, 

 involving the anteunal nerve; in the succeeding section the olfactory lobes of both sides are 

 involved, and the left antennal nerve in the five succeeding sections are represented in Pigs. 8 

 and '.'. 



Pig. 10 is an enlarged view of the section represented by Pig. 8. The cortical layer of 

 ganglion cells supplying the tangled fibers composing the central myeloid substance is well devel- 

 oped ; and here it should be observed that, as in Pseudotremia and the Chilopod brains examined, 

 the ganglion cells are very small and numerous, with a distinct central nucleus rather thau scat- 

 tered nucleoli. The fibers from the upper surface of the brain on each side of the median liue 

 are seen to form two bundles, passing towards the center of each procerebral lobe. The olfactory 

 lobes are well developed, and on the left side the portions in the section were darker, more clouded, 

 than the myeloid substance elsewhere. 



In this section were observed' in the median line of the brain seven small areas, which remind 

 one of the so-called central body of the insects. If these bodies, which are perhaps sections of 

 bundles of fibers passing longitudinally through the middle of the braiu, should prove to be 

 homologous to the ^central body" of insects, it will form an additional point of resemblance 

 between the brains of Myriopods and the winged insects. But they need further examination and 

 comparison with other out-of door Myriopods. 



THE ANATOMY OP THE BRAIN OP ANOPHTHALMUS TELLKAMPPII. 

 (PI. XXII, figs. 1-4, 4a-4/.) 



In order to understand the modifications in the brain of Anophthalmus due to a life in per- 

 petual darkness we should compare it with the normal brain of another member of the same 

 natural family, in which the eyes and brain are normal. It would be better, of course, if we could 

 have examined that of a Trechus, but this has not been possible, PI. XXII, fig. 1, represents a dis- 

 section of the head, with the eyes and brain, of a Carabid beetle, CMcenius pensylvaniciis. Seen 

 from above, after removing the integument and surrounding tissues and muscles, the brain of 

 Chlsenius is, like the other members of its family and beetles in general, composed of two pro- 

 cerebral lobes {pel.), with the well-developed antennal lobes in front, from which the antennal 

 nerves (ant.) take their origin. On each side, between the brain (procerebrum) and eye, is situated 

 the optic ganglion (op. g), which in Chiasmus is large and well developed, indeed only about a 

 fourth smaller than a procerebral lobe. The eye is large and well developed. 



Comparing with Chlsenius the brain of Anophthalmus, it will be seen by a glance at PI. 

 XXII, fig. 2, that there is a total absence of the optic ganglia and eyes. Traces of neither 

 can be detected in gross dissections or numerous horizontal, transverse, and longitudinal sec- 

 tions. It will be seen that the procerebral lobes are well developed, as well as the antennal 

 lobes, an antennal nerve passing into each antenna. 



The general relations of the brain (snpraoesophageal ganglion) to thesuboesopbageal ganglion 

 and other parts of the nervous system in the head are in part shown in PI. XXII, figs. 3 and 3 a, 

 which represent a median longitudinal section of the head of Anophthalmia ; pel. represents the 

 brain or procerebrum, which is separated from the subcesophageal ganglion (see.) by the oesophagus 

 (ce.). From the lower anterior aspect of the procerebrum passes a nerve to the frontal ganglion 

 (/(/.), and from it a nerve passes toward the labrum (Ibr.). On the upper anterior aspect of the sub- 

 oesophageal ganglion is what may be called the lingual ganglion, from which arises the lingual 

 nerve (I. ».), which supplies the lingua (I.). From a larger, more laterally and ventrally situated 

 pair of lobes arise a nerve (mx. n.) giving origin to the (first and second) maxillary nerves. 



The horizontal microscopic sections represented by Figs. 4-4 c show that the optic ganglion, as 

 well as the cornea, cones, rods, and retina, are all absent, with not even the rudiments left. Fig. 4ft 

 represents the procerebral lobes, with the antennal lobes in front (ant. /.), from which arise the 

 antennal nerve (ant. n.). Fig. 4 d represents the two small lobes at the base of the antennal nerves, 

 which have apparently been hitherto overlooked. 



Vertical suctions of the brain are seen in Figs. 4e-4i7. In these and other sections of this 

 beetle no traces of the so-called "central body," or mushroom body, with its calyces, have been 



