. The Bashford Dean memorial volume :. Fishes; Sharks; Fishes, Fossil. The Anatomy of Chlamydoselachus 489 THE SENSORY CANAL SYSTEM The distribution of the sensory canals of Chlamydoselachus has been described by Garman (1888), Hawkes (1906) and AUis (1923 and 1934). Their descriptions have been briefly reviewed by Gudger and Smith (1933), who added some observations on the specimens in the American Museum of Natural History. This account, which is fairly well illustrated, need not be repeated here. Some of the sensory canals of the head are shown in my Text'figure 70, page 396; and in Text'fi
. The Bashford Dean memorial volume :. Fishes; Sharks; Fishes, Fossil. The Anatomy of Chlamydoselachus 489 THE SENSORY CANAL SYSTEM The distribution of the sensory canals of Chlamydoselachus has been described by Garman (1888), Hawkes (1906) and AUis (1923 and 1934). Their descriptions have been briefly reviewed by Gudger and Smith (1933), who added some observations on the specimens in the American Museum of Natural History. This account, which is fairly well illustrated, need not be repeated here. Some of the sensory canals of the head are shown in my Text'figure 70, page 396; and in Text'figure 124. The innervation of the sensory canals of the head has been worked out by Hawkes (1906), whose drawing is reproduced as my Figure 29, plate VII. For comparison, I have inserted a similar figure (Text-figure 125) representing the sensory canals of the head in Squalus. It remains to con- sider the sensory canal system of Chlamy^ doselachus briefly from a comparative point of view. In all adult elasmobranchs, the sen- sory canals are fairly similar in their dis- tribution. A pair of these canals extend in or under the skin, from the tip of the tail to the vicinity of the ear, where they connect with other canals branching over the various regions of the head. At inter- vals, the canals open to the exterior by means of pores, so that their approximate distribution can usually be traced without dissection. Among living elasmobranchs it is very unusual for the sensory canals to be present as open grooves through so great. _ i iamp Text-figure 124. Dorsal view of the head of Chlamydoselachus, show- ing the external openings of the ampullae of Lorenzini and of the laterosensory canals. amp, ampuUary pores; end, pore of the endolymphatic duct; iop, infraorbital laterosensory pores; lie, lateral line canal of body; sop, supraorbital laterosensory pores; sp, spiracular laterosensory canal; spr, spiracle. Redrawn after Allis, 1923, Pi. 11. a portion of their extent as is the case
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